Scaffold structure

ABSTRACT

A scaffold structure comprising a ladder assembly that is maintained in a substantially vertical orientation during use by means of two arms extending outwardly from two support members and that are mounted on the support members for sliding movement along substantially the whole length of the support members and legs mounted at the bottom of the support members. The scaffold structure also comprises a vertically positionable platform assembly connected to the ladder assembly for vertical movement therealong and connected to the assembly by means of connecting members disposed about the outboard side of the support members for sliding movement along the support members.

United States Patent 191 N man Oct. 7, 1975 [5 SCAFFOLD STRUCTURE3,490,558 1/1970 Foley 182/103 N 'll [76] Inventor i fg 2: 5: Bldalsgatan Primary Examiner-Paul R. Gilliam Assistant Examiner-David H.Corbin [22] Filed: Dec. 5, 1973 Attorney, Agent, or FirmRobert E. Burns;[211 App] NO 421 865 Emmanuel J. Lobato; Bruce L. Adams Related US.Application Data Continuation-impart of Ser. No. 400,613, Sept. 25,1973, abandoned, which is a continuation of Ser. No. 89,344, Nov. 13,1970, Pat. No. 3,770,902.

[52] US. Cl 182/103; 182/214 [51] Int. C1. E06C 7/16 [58] Field ofSearch 182/102, 103, 122, 214

[56] References Cited UNITED STATES PATENTS 800,896 10/1905 Biehler182/214 X 837,006 11/1906 Spaull et al. 182/103 843,989 2/1907 Bauer182/214 X 1,800,792 4/1931 Hansen... 182/214 1,969,628 8/1934 Skeenes..182/103 X 2,245,661 6/1941 Fieroh 182/122 X [5 7 ABSTRACT A scaffoldstructure comprising a ladder assembly that is maintained in asubstantially vertical orientation during use by means of two armsextending outwardly from two support members and that are mounted on thesupport members for sliding movement along substantially the wholelength of the support members and legs mounted at the bottom of thesupport members. The scaffold structure also comprises a verticallypositionable platform assembly connected to the ladder assembly forvertical movement therealong and connected to the assembly by means ofconnecting members disposed about the outboard side of the supportmembers for sliding movement along the support members.

18 Claims, 3 Drawing Figures Sheet 1 of 2 3,910,378

FIG 2 U.S. Patent Oct. 7,1975

U.S. Patent Oct. 7,1975 Sheet 2 of2 3,910,378

SCAFFOLD STRUCTURE CROSS-REFERENCE TO RELATED APPLICATIONS Thisapplication is a continuation-in-part of the US. Patent application Ser.No. 400,613 filed on Sept. 25, 1973 and now abandoned, which is acontinuation of the US. patent application Ser. No. 89,344, filed onNov. 13, 1970 and now US. Pat. No. 3,770,902.

BACKGROUND OF THE INVENTION The present invention relates to a scaffoldstructure comprising a ladder assembly and a platform assembly.

Known scaffold structures for use in exterior work, such as painting,have many disadvantages. One of these disadvantages is that the securingof the scaffold structures, against buildings or where stress forces areencountered, offer great difficulties which have not been overcomesatisfactorily by the known structures. In addition, a simple anduncomplicated anchoring of the platform has not been provided.Furthermore, the prior art scaffold structures do not provide an easyand convenient vertical adjustment of the platform assembly or of thevarious structural members that are used to orient the ladder assemblyin a substantially vertical direction.

SUMMARY OF THE INVENTION Therefore. it is an object of the presentinvention to eliminate the disadvantages of the prior art scaffoldstructures by providing a reliable and simple scaffold structure havingan equally reliable and simple vertically adjustable platform assembly.

Another object of the present invention is to provide a simple means formounting the platform assembly to the ladder assembly for movement alongthe length of the ladder assembly.

A further object of the present invention is to provide a simplestructure for maintaining the ladder assembly in a substantiallyvertical orientation and a simple and reliable structure for connectingthis structure to the ladder assembly so that it is slidable therealong.

Still another object of the present invention is to provide structurefor effecting the longitudinal movement of the structure for maintainingthe ladder assembly in a substantially vertical orientation along thelength of the ladder assembly.

A still further object of the present invention is to provide anapparatus for locking the platform assembly to the ladder assembly tokeep it in a working position and for easily and simply releasing it formovement to another working position. V

In accordance with the objects of the present invention. a scaffoldstructure is provided comprising a ladder assembly having a pairofjuxtaposed and spaced apart elongated support members, a plurality ofrungs interconnecting the support members at a plurality of longitudinalspaced-apart locations and means connected to the support members formaintaining the ladder assembly in a substantially vertical orientationduring use wherein the support members extend in a generally verticaldirection. The means for maintaining the ladder assembly in asubstantially vertical orientation comprises two arms extendingoutwardly from the support members and lying in'a plane generallyperpendicular to that of the support members, means mounting the arm onthe support members for sliding movement along substantially the wholelength of the support members and manually actuatable means foreffecting movement of the arms along the length of the support members.The means mounting the arms on the support members comprises a pair ofconnecting members each disposed about and slidable along the outboardside of one of the support members and connected to one of the arms anda connecting rod interconnecting both connecting members.

The scaffold structure also comprises a vertically positionable platformassembly movably connected to the ladder assembly for vertical movementtherealong and defining therewith a scaffold structure. The verticallypositionable platform assembly comprises a base portion extendingoutwardly from the support members in the same direction as the arms anddimensioned to accommodate thereon a standing person when the ladderassembly is vertically orientated, means movably connecting the platformassembly to the ladder assembly for movement therealong,- locking meansconnected to the platform assembly and coacting with the rungs forreleasably locking the platform assembly in a predetermined workingposition along the ladder assembly and means engagable with a personascending or descending the ladder' assembly for effecting correspondingvertical ascending or descending movement of the platform assembly alongthe support members. As a result of this structure, a platform assemblymay be vertically moved or positioned along the ladder assembly by theascending or descending movement of a person along the ladder assembly.

The locking means comprises a pair of pivotally mounted locking membersmanually pivotable towards the ladder assembly to releasably bearagainst and engage with a common one of the rungs to lock the platformassembly in the working position and manually pivotable away from theladder assembly to disengage the locking members from the common rung tothereby permit movement of the platform assembly along the supportmembers. A connecting rod interconnects the pair of locking connectorsand mounts them for pivotal movement together as integral unit and apair of manually actuatable levers are each connected to one of thelocking members and movable away from the ladder assembly to releasablyengage both locking members with a common'rung and movable towards theladder assembly to disengage locking members from the rung.

The means movably connecting the platform assembly to the ladderassembly for movement therealong comprises at least one pair ofconnecting members each disposed about the outboard side of one of thesupport members for sliding movement therealong and a connecting rod forconnecting the pair of connecting members together.

Each of the support members has either an I-shaped cross-section or achannel in the outboard side having a web portion and two flangeportions. Each pair of connecting members has a generally C-shapedcrosssection configured to closely fit about the outboard portions ofboth flange portions The manually actuatable means for effectingmovement of the arms along the length of the support members comprises aclosed loop of cord looped around the plurality of rungs and connectedat one portion to the connecting rod interconnecting the pair ofconnecting members connected to the arms.

Having in mind the above and other objects that will be obvious from anunderstanding of the disclosure, the present invention comprises thecombination and arrangement of parts illustrated in the presentlypreferred embodiment of the present invention which are hereinafter setforth in sufficient detail to enable those persons skilled in the art toclearly understand the function, operation, construction, and advantagesof it when read in with with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of thewhole scaffold structure in accordance with the present invention;

FIG. 2 is perspective view of the upper part of the scaffold structurein accordance with the present invention; and

FIG. 3 is perspective view of the platform assembly movably connected tothe ladder assembly according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings, ladderassembly 1 has a pair of juxtaposed and spaced apart elongated supportmembers 2 and a plurality of rungs 3 interconnecting these supportmembers 2 at a plurality of longitudinally spaced apart locations. Theladder assembly is preferably made from light metal and the rungsconsist of round or square tubes preferably having an outer corrugatedcross-section to prevent slipping when in use. The support members 2have a channel therein on the outboard side thereof and they preferablycomprise beams having an l-shaped cross-section having a webportion 2aand two flange portions 2b.

The ladder assembly 1 is maintained in a substantially verticalorientation during use wherein the support members 2 extend in agenerally vertical direction by means of two arms 11 extending outwardlyfrom the support members 2 and lying in a plane generally per-.pendicular to that of the support members 2. The arms abut against awall or similar structure during use of the scaffold assembly. The arms11 are mounted on the support members 2 for sliding movement alongsubstantially the whole length of the support members by a pair ofconnecting members 12 having a C-shaped cross-section and configured toclosely fit about the outboard side of the support members 2. Theconnecting members 12 are disposed about and slidable along the outboardside of the support members 2 and are connected to the arms by members8. A connecting rod 13, shown in H0. 2, interconnects both connectingmembers 12 and another interconnecting rod 9 interconnects the arms 11to provide further stabilization of the arms 11. Manually actuatablemeans for effecting movement of the arms 11 along the length of thesupport members 2 comprises a closed loop of cord 14 looped around aplurality of rungs 3 and connected at one end portion at connector 15 tothe connecting rod 13. The operator of the scaffold structure can loweror raise the arms 11 by pulling the rope or cord 14 at the side of theladder assembly from which the arms project or the opposite side,respectively.

The means maintaining the ladder assembly in the vertical orientationfurther comprises two legs 17 bracing the lower portion of the ladderassembly 1 and fastened to the outboard side of the lower end of thesupport members 2 by the nut and bolt assembly 41. The

legs 17 each consists of two metal tubes 18 and by feet 19. The legs 17projects sideways and preferably away from the building or wall uponwhich arms 11 rests during use.

Connected to the ladder assembly is a vertically positionable platformassembly 20. The platform assembly is connected to the ladder assembly 1for vertical movement thercalong to define with the ladder assembly thescaffold structure. The platform assembly is movably connected to theladder assembly by means of two pairs of connecting members 22 and 26.Each con-' necting member is disposed about the outboard side of one ofthe support members 2 for sliding movement therealong. The connectingmembers have a C-shaped cross-section and are configured to closely fitabout the outboardportion of the support member 2. The connectingmembers 22 are interconnected by a connecting rod 23. The pairs ofconnecting members 22 and 26 on each support member are connectedtogether by means of rods 25. The rods 25 terminate at base portion 21which is connected to both rods 25 and another pair of connecting rods24 provide further support, Rods 25 are also connected toconnectingmembers 22. The connecting members 22 are also interconnected by anarcuate connecting rod 27 which is pivotally mounted at connectingmembers 22 in order to enable the user of the scaffold structure toconveniently leave and enter the platform assembly 20 by raising andlowering the arcuate connecting rod 27.

The platform assembly 20 is also provided with locking means which coactwith the rungs 3 for releasably locking the platform assembly 20 in apredetermined working position along the ladder assembly. The lockingmeans comprises a pair of pivotally mounted locking members 31 pivotallymounted on connecting rod 32 to move therewith as an integral unit. Thelocking members 31 are pivotable towards the ladder assembly toa lockingposition wherein they engage with a common one of the rungs 3a to lockthe platform assembly in the working position and manually pivotable,away from the ladder assembly to an unlocking position wherein theydisengage the locking members 31 from common rung 3a to thereby permitmovement of the platform assembly along the support members 2. As seenin the drawings, the bottom ends of the locking members 31 havesubstantially flat end faces which are pivotable to rest upon and bearagainst a common one of the rungs 3 to engage therewith when the lockingmembers are pivoted to their locking position. A pair of manuallyactuatable levers 33 are each connected to one of the locking members 31and are movable away from the ladder assembly to releasably. engage bothlocking members with a common rung 3a and movable toward the ladderassembly to disengage the locking members from the rung 3a. The leversare positioned at the level of the breast region of a person standing onthe base portion to enable the person to easily reach and move thelevers 33 to pivot the locking members 31.

The platform assembly 20 also has means engagable with a personascending or descending the ladder assembly 1 for effectingcorresponding vertical ascending or descending movement of the platformassembly 20 along the support members 2 when the locking members 31 aredisengaged from the common rung 3a. This means comprises a strap member40 having two end.

portions 40a connected to the rod 32. The strap is positioned relativeto the base portion to fit around the back of the neck and shoulder of aperson both facing the ladder assembly and standing on the rung 3b ofthe ladder assembly located adjacent to the base portion as shown inFIG. 3.

The operation of the scaffold structure in accordance with-the presentinvention will now be explained. The scaffold structure is placed in theposition shown in FIG. 1 with the arms 11 abutting against a building orwall. The cord or rope 14 is pulled from either side of the ladderassembly 1 to raise or lower the arms to a desired height so that itsafely abuts against a wall or building. The operator then raises thearcuate connecting rod 27 and enters the platform assembly 20. Theoperator then places the strap 40 around his neck and climbs on to rung3b as shown in FIG. 3. He then disengages the locking members 31 fromrung 30 by use of the manually actuatable levers 33 thereby releasingthe platform assembly for slidable movement along the support members 2.The operator then climbs on the rungs 3 until he reaches the desiredheight for the platform assembly and then pivots the levers 33 away fromthe ladder assembly to engage the locking members 31 on a common rungthereby lockingthe platform assembly in the desired working position.The operator is then able to remove the strap from the back of his neckand be supported by the base 21, to accomplish his ap pointed task.

While preferred embodiments of the invention have been shown by way ofexample in the drawings, it will be understood that the invention is inno way limited to these embodiments.

What I claim is: H

1. A scaffold structure comprising: a ladder assembly having a pair ofjuxtaposed and spaced-apart elongated support members, a pluralityofrungs interconnecting said support members at a plurality oflongitudinallyspaced-apart locations, and means connected to saidsupport members for maintaining said ladder assembly in a substantiallyvertical orientation during use so that said support members extend in agenerally vertical direction comprising two arms extending outwardlyfrom said support members and lying in a plane generally perpendicularto that of said support members, means mounting said arms on saidsupport members for sliding movement along substantially the wholelength of said support members comprising a first pair of connectingmembers each disposed about and slidable along the outboard side ofrespective ones of said support members and connected to one of saidarms and means including a connecting rod interconnecting bothconnecting members, and manually actuatable means for effecting movementof said arms along the length of said support members; and a verticallypositionable platform assembly movably connected to said ladder assemblyfor vertical movement therealong and defining therewith a scaffoldstructure, said platform assembly comprising a base portion extendingoutwardly from said support members in the same direction as said armsand dimensioned to accommodate thereon a standing person when saidladder assembly is vertically orientated, means movably connecting saidplatform asembly to said ladder assembly for movement therealong,locking means connected to said platform assembly and coacting with saidrungs for releasably locking said platform assembly in a predeterminedworking l'f'i lllOn along said ladder assembly and comprising a pair ofpivotally mounted locking members having at one end substantially flatend faces and means mounting said locking members for manual pivotalmovement to a locking position wherein said flat end faces rest upon andbear against a common one of said rungs to thereby releasably lock saidplatform assembly in said working position and to an unlocking positionwhereinsaid flat end faces are free of said rungs to thereby permitmovement of said platform assembly along said support members, and meansengageable with a person ascending or descending said ladder assembly.for effecting corresponding vertical ascending or descending movement ofsaid platform assembly along said support members; whereby said platformassembly may be vertically moved and positioned along said ladderassembly by the ascending or descending movement of a person along saidladder assembly.

2. A scaffold structure according to claim 1; wherein said locing meansincludes a connecting rod interconnecting said pair of locking membersand mounting same for pivotal movement together as an integral unit anda pair of manually actuatable levers each con nected to one of saidlocking members and pivotally movable away from said ladder assembly toeffect pivotal movement of said locking members into said lockingposition and pivotally movable towards said ladder assembly to effectpivotal movement of said locking members to said unlocking position.

3. A scaffold structure according to claim 2, wherein said levers arepositioned at the level of the breast region ofa person standing on saidbase portion to enable the person to easily reach and move said leversto pivot said locking members.

4. A scaffold structure according to claim 1; wherein said meansengagable with a person comprises a strap member connected to anddepending from said platform assembly and positioned relative to saidbase portion to fit around the back of the neck and shoulder of a personboth facing said ladder assembly and standing on the rung of the ladderassembly located adjacent said base portion.

5. A scaffold structure according to claim 4; wherein said strap memberhas two end portions respectively connected to and suspended betweensaid pair of locking members.

6. A scaffold structure according to claim 1; wherein said means movablyconnecting said platform assembly to said ladder assembly includes meansincluding at least one second pair of connecting members each disposedabout and slidable along the outboard side of re spective ones of saidsupport members, connecting rod interconnecting said second pair ofconnecting members and wherein said platform assembly includes aplurality of connecting bars interconnecting said base portion to saidsecond pair of connecting members.

7. A scaffold structure according to claim 6; wherein said supportmembers each have an Ishaped crosssection having a web portion and twoflange portions and wherein each pair of connecting members have agenerally C-shaped cross-section configured to closely fit about theoutboard portion of both flange portions.

8. A scaffold structure according to claim 1; wherein said manuallyactuatable means comprises a closed loop or cord looped around aplurality of rungs and connected at one portion to said connecting rod.

9. A scaffold structure according to claim 1; wherein said supportmembers each have means defining a channel in the outboard side, thereofand wherein said first pair of connecting members have a generally C-shaped cross-section configured to closely fit about the outboard sideof said support members.

10. A scaffold structure comprising: a ladder assembly having a pairofjuxtaposed and spaced-apart elongated support members, a plurality ofrungs interconnecting said support members at a plurality oflongitudinally spaced-apart locations, and means connected to saidsupport members for maintaining said ladder assembly in a substantiallyvertical orientation during use so that said support members extend in agenerally vertical direction; and a vertically. positionable platformassembly movably connected to said ladder assembly for vertical movementtherealong and defining therewith a scaffold structure, said platformassembly comprising a base portion extending outwardly from said supportmembers and dimensioned to accommodate thereon a standing person whensaid ladder assembly is vertically orientated, means movably connectingsaid platform assembly to'said ladder assembly for movement therealongcomprising at least one first pair of connecting members each disposedabout the outboard side of one of said support members for slidingmovement therealong and a first connecting rod connecting said firstpair of connecting members together, locking means connected to saidplatform assembly and coacting with said rungs for releasably lockingsaid platform assembly in a predetermined working position along saidladder assembly and comprising a pair of pivotally mounted lockingmembers having at one end substantially flat end faces and meansmounting said locking members for manual pivotal movement to a lockingposition wherein said flat end faces rest upon and bear against a commonone of said rungs to thereby releasably lock said platform assembly insaid working position and to an unlocking position wherein said flat endfaces are free of said rungs to thereby permit movement of siad platformassembly along said support members, and means engageable with a personascending or descending said ladder assembly for effecting correspondingvertical ascending or descending movement of said platform assemblyalong said support members; whereby said platform assembly may bevertically moved and positioned along said ladder assembly by theascending or descending movement of a person along said ladder assembly.

11. A scaffold structure according to claim 10;

wherein said locking means includes a connecting rod interconnectingsaid pair of locking members and mounting same for pivotal movementtogether as an in-' said ladder assembly to effective pivotal. movabletowards said ladder assembly to effect pivotal movement of said lockingmember to said unlocking position.

12. A scaffold structure according to claim 11, wherein said levers arepositioned at the level of the breast region of a person standing onsaid base portion to enable the person to easily reach and movesaidlevers to pivot said locking members.

13. A scaffold structure according to claim 10; wherein said meansengagcablc with a person comprises a strap member connected to anddepending from said platform assembly and positioned relative to saidbase portion to fit around the back of the neck and shoulder of a personboth facing said ladder assembly and standing on the rung ofthe ladderassembly located adjacent said base portion.

14. A scaffold structure according to claim 13; wherein said strapmember has two end portions re-, spectively connected to and suspendedbetween said pair of locking members.

15. A scaffold structure according to claim 10;. wherein said means formaintaining said ladder assembly in a substantially vertical orientationcomprises two arms extending outwardly fromsaid support members in thesame direction as said base portion and lying in a plane generallyperpendicular to that of said support members, means mounting said armson said support members for sliding movement along substantially thewhole length of said support members comprising a second pair ofconnecting members each disposed about and slidable along the outboardside of one of said support members and connected to one of said arms,means including a connecting rod interconnecting both connecting membersand manually actuatable means for effecting movement of said arms alongthe length of said support members.

16. A scaffold structure according to claim 15; wherein said supportmembers each have an l-shaped cross-section having a web portion andtwoflange portions and wherein each pair of connecting members have agenerally C-shaped cross-section configured to.

closely fit about the outboard portion of both flange portions.

17. A scaffold structure according to claim 15; wherein said manuallyactuatable means comprises a closed loop of cord looped around aplurality of rungs and connected at one portion to said connecting rod.

18. A scaffold structure according to claim 10; wherein said supportmembers each have means defining a channel in the outboard side thereofand wherein said first pair of connecting members have a generallyC-shaped cross-section configured to closely fit about the outboard sideof said support members.

l l= l l

1. A scaffold structure comprising: a ladder assembly having a pair ofjuxtaposed and spaced-apart elongated support members, a plurality ofrungs interconnecting said support members at a plurality oflongitudinally spaced-apart locations, and means connected to saidsupport members for maintaining said ladder assembly in a substantiallyvertical orientation during use so that said support members extend in agenerally vertical direction comprising two arms extending outwardlyfrom said support members and lying in a plane generally perpendicularto that of said support members, means mounting said arms on saidsupport members for sliding movement along substantially the wholelength of said support members comprising a first pair of connectingmembers each disposed about and slidable along the outboard side ofrespective ones of said support members and connected to one of saidarms and means including a connecting rod interconnecting bothconnecting members, and manually actuatable means for effecting movementof said arms along the length of said support members; and a verticallypositionable platform assembly movably connected to said ladder assemblyfor vertical movement therealong and defining therewith a scaffoldstructure, said platform assembly comprising a base portion extendingoutwardly from said support members in the same direction as said armsand dimensioned to accommodate thereon a standing person when saidladder assembly is vertically orientated, means movably connecting saidplatform asembly to said ladder assembly for movement therealong,locking means connected to said platform assembly and coacting with saidrungs for releasably locking said platform assembly in a predeterminedworking position along said ladder assembly and comprising a pair ofpivotally mounted locking members having at one end substantially flatend faces and means mounting said locking members for manual pivotalmovement to a locking position wherein said flat end faces rest upon andbear against a common one of said rungs to thereby releasably lock saidplatform assembly in said working position and to an unlocking positionwherein said flat end faces are free of said rungs to thereby permitmovement of said platform assembly along said support members, and meansengageable with a person ascending or descending said ladder assemblyfor effecting corresponding vertical ascending or descending movement ofsaid platform assembly along said support members; whereby said platformassembly may be vertically moved and positioned along said ladderassembly by the ascending or descending movement of a person along saidladder assembly.
 2. A scaffold structure according to claim 1; whereinsaid locing means includes a connecting rod interconnecting said pair oflocking members and mounting same for pivotal movement together as anintegral unit and a pair of manually actuatable levers each connected toone of said locking members and pivotally movable away from said ladderassembly to effect pivotal movement of said locking members into saidlocking position and pivotally movable towards said ladder assembly toeffect pivotal movement of said locking members to said unlockingposition.
 3. A scaffold structure according to claim 2, wherein saidlevers are positioned at the level of the breast region of a personstanding on said base portion to enable the person to easily reach andmove said levers to pivot said locking members.
 4. A scaffold structureaccording to claim 1; wherein said means engagable with a personcomprises a strap member connected to and depending from said platformassembly and positioned relative to said base portion to fit around theback of the neck and shoulder of a person both facing sAid ladderassembly and standing on the rung of the ladder assembly locatedadjacent said base portion.
 5. A scaffold structure according to claim4; wherein said strap member has two end portions respectively connectedto and suspended between said pair of locking members.
 6. A scaffoldstructure according to claim 1; wherein said means movably connectingsaid platform assembly to said ladder assembly includes means includingat least one second pair of connecting members each disposed about andslidable along the outboard side of respective ones of said supportmembers, connecting rod interconnecting said second pair of connectingmembers and wherein said platform assembly includes a plurality ofconnecting bars interconnecting said base portion to said second pair ofconnecting members.
 7. A scaffold structure according to claim 6;wherein said support members each have an I-shaped cross-section havinga web portion and two flange portions and wherein each pair ofconnecting members have a generally C-shaped cross-section configured toclosely fit about the outboard portion of both flange portions.
 8. Ascaffold structure according to claim 1; wherein said manuallyactuatable means comprises a closed loop or cord looped around aplurality of rungs and connected at one portion to said connecting rod.9. A scaffold structure according to claim 1; wherein said supportmembers each have means defining a channel in the outboard side thereofand wherein siad first pair of connecting members have a generallyC-shaped cross-section configured to closely fit about the outboard sideof said support members.
 10. A scaffold structure comprising: a ladderassembly having a pair of juxtaposed and spaced-apart elongated supportmembers, a plurality of rungs interconnecting said support members at aplurality of longitudinally spaced-apart locations, and means connectedto said support members for maintaining said ladder assembly in asubstantially vertical orientation during use so that said supportmembers extend in a generally vertical direction; and a verticallypositionable platform assembly movably connected to said ladder assemblyfor vertical movement therealong and defining therewith a scaffoldstructure, said platform assembly comprising a base portion extendingoutwardly from said support members and dimensioned to accommodatethereon a standing person when said ladder assembly is verticallyorientated, means movably connecting said platform assembly to saidladder assembly for movement therealong comprising at least one firstpair of connecting members each disposed about the outboard side of oneof said support members for sliding movement therealong and a firstconnecting rod connecting said first pair of connecting memberstogether, locking means connected to said platform assembly and coactingwith said rungs for releasably locking said platform assembly in apredetermined working position along said ladder assembly and comprisinga pair of pivotally mounted locking members having at one endsubstantially flat end faces and means mounting said locking members formanual pivotal movement to a locking position wherein said flat endfaces rest upon and bear against a common one of said rungs to therebyreleasably lock said platform assembly in said working position and toan unlocking position wherein said flat end faces are free of said rungsto thereby permit movement of siad platform assembly along said supportmembers, and means engageable with a person ascending or descending saidladder assembly for effecting corresponding vertical ascending ordescending movement of said platform assembly along said supportmembers; whereby said platform assembly may be vertically moved andpositioned along said ladder assembly by the ascending or descendingmovement of a person along said ladder assembly.
 11. A scaffoldstructure according to claim 10; wherein said locking means includes aconnecting rod interconnecting said pair of locking members and mounTingsame for pivotal movement together as an integral unit and a pair ofmanually actuatable levers each connected to one of said locking membersand pivotally movable away from said ladder assembly to effect pivotalmovement of said locking members into said locking position andpivotally movable towards said ladder assembly to effective pivotalmovable towards said ladder assembly to effect pivotal movement of saidlocking membes to said unlocking position.
 12. A scaffold structureaccording to claim 11, wherein said levers are positioned at the levelof the breast region of a person standing on said base portion to enablethe person to easily reach and move said levers to pivot said lockingmembers.
 13. A scaffold structure according to claim 10; wherein saidmeans engageable with a person comprises a strap member connected to anddepending from said platform assembly and positioned relative to saidbase portion to fit around the back of the neck and shoulder of a personboth facing said ladder assembly and standing on the rung of the ladderassembly located adjacent said base portion.
 14. A scaffold structureaccording to claim 13; wherein said strap member has two end portionsrespectively connected to and suspended between said pair of lockingmembers.
 15. A scaffold structure according to claim 10; wherein saidmeans for maintaining said ladder assembly in a substantially verticalorientation comprises two arms extending outwardly from said supportmembers in the same direction as said base portion and lying in a planegenerally perpendicular to that of said support members, means mountingsaid arms on said support members for sliding movement alongsubstantially the whole length of said support members comprising asecond pair of connecting members each disposed about and slidable alongthe outboard side of one of said support members and connected to one ofsaid arms, means including a connecting rod interconnecting bothconnecting members and manually actuatable means for effecting movementof said arms along the length of said support members.
 16. A scaffoldstructure according to claim 15; wherein said support members each havean I-shaped cross-section having a web portion and two flange portionsand wherein each pair of connecting members have a generally C-shapedcross-section configured to closely fit about the outboard portion ofboth flange portions.
 17. A scaffold structure according to claim 15;wherein said manually actuatable means comprises a closed loop of cordlooped around a plurality of rungs and connected at one portion to saidconnecting rod.
 18. A scaffold structure according to claim 10; whereinsaid support members each have means defining a channel in the outboardside thereof and wherein said first pair of connecting members have agenerally C-shaped cross-section configured to closely fit about theoutboard side of said support members.